An experiment to see if we can charge a LiFePO4 cell in the cold, at -17C. From the test results we can see that very little current goes into the empty battery even when the power supply is set to 3.6V. After warming up, we can charge at full current. From the capacity test after a full charge we don’t see any immediate damage – we draw full capacity. This might be different if we only charge at temperatures slightly below 0C.